Many residences and businesses include a network of inter-connected devices (“network devices”) that are able to communicate with each other using a communications protocol, such as Internet Protocol (IP). The network devices may use one or more communications links for communicating with each other, e.g., transmitting messages and data on a cable line, a phone line or via wireless transmissions. The network devices may include personal computers (PCs), work station computers, media display devices, audio devices, telephones, and wireless devices, for example. In some cases the network is implemented as a peer-to-peer network, with devices communicating directly to other devices. In other cases, a network may include a gateway device (or router device) that operates as a data forwarding device, i.e., receiving data from a first network device and forwarding that data to another network device. The gateway device may also be coupled to communicate with another network of devices, such as a wide area network (WAN), i.e., the Internet.
A network of inter-connected devices installed at a home or business is sometimes referred to as a Small Office or Home Office (SOHO) network. The data transferred between network devices is sometimes referred to as “media”, which refers to the various types of information that may be represented by the data, for example, text, pictures, video and voice.
UPnP™ refers to an industry-standard architecture that may be used by applications executing on networked devices to advertise, discover and control services that are available on those networked devices. A network device executing a UPnP™ application may announce its presence on a SOHO network and advertise the services available on that device. UPnP™ architecture also includes a definition of a “control point” which refers to a device that is capable of discovering and controlling services on other devices executing a UPnP™ application.
UPnP™ messages are typically sent on a network communications link using industry-standard protocols, such as Internet Protocol (IP) and Hyper Text Transfer Protocol (HTTP).
UPnP™ architecture includes a variety of terms to refer to physical and logical objects. Each physical device may have embedded physical or logical devices, for example, a combination TV/VCR player may have two embedded devices, one for the TV monitor/display component and a second for the VCR/tape-player component. Each physical device, or embedded device, will include an associated service (or services) that refer to the functions that may be performed by that device.